Catalysts for oxidation of lower olefins to unsaturated aldehydes, methods of making and using the same

ABSTRACT

The present invention provides a catalyst composition for the production of unsaturated aldehydes by the oxidation of the corresponding olefins, and methods of making and using such catalyst compositions. The catalysts of the present invention include compositions of the formula: 
     Mo a Pd b Bi c Fe d X 1   e X 2   f X 3   g O z , 
     wherein X 1  is an element selected from Co, Ni, V, Pt, Rh, or mixtures thereof; X 2  is an element selected from Al, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, W, or mixtures thereof; X 3  is an element selected from K, Mg, Rb, Ca, Sr, Ba, Na, In, or mixtures thereof; a is 1; b is 0&lt;b&lt;0.3; c is 0&lt;c&lt;0.9; d is 0&lt;d&lt;0.9; e is 0&lt;e&lt;0.9; f is 0&lt;f&lt;0.9; g is 0&lt;g&lt;0.3; and z is an integer representing the number of oxygen atoms required to satisfy the valency of Mo, Pd, Bi, Fe, X 1 , X 2 , and X 3  in the catalyst composition. Using the methods of the present invention, one may effectively oxidize the desired starting materials at relatively high levels of conversion, selectivity, and productivity, and with minimal side products.

[0001] The redox characteristic of a mixed metal oxide catalyst is a keyfactor in controlling the activity and oxygenation function of thecatalyst. These characteristics depend on the type of metal oxide mixedand their concentration. See, “Oxidative Dehydrogenation of Lower Alkaneon Vanadium Based Catalysts”. by E. Mamedov and V. Corberan, AppliedCatalysis, vol. 217, pages 1-40 (1995). It would be desirable to derivea catalyst composition containing a specific combination of metalelements with suitable properties or characteristics to generate a redoxcharacteristic catalyst having a significant impact on the selectivityand productivity of the oxygenation process. The mixed metal oxidecatalysts of the present invention are prepared by an appropriatecombination of the metal components, yielding a catalyst with a uniqueability to selectively oxidize olefins to alpha-beta unsaturatedaldehydes.

SUMMARY OF THE INVENTION

[0002] The present invention relates to the selective oxidation ofhydrocarbons or olefins in the presence of molecular oxygen to formalpha-beta unsaturated aldehydes. This gas phase reaction is preferablycarried out using a mixed metal oxide catalyst at temperatures in therange of 150° C. to 450° C. and at pressures of 1-50 bar. As a result,the method of the present invention achieves relatively high rates ofselectivity and productivity.

[0003] The catalysts of the present invention are mixed metal oxides ofthe general formula

Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z),

[0004] wherein:

[0005] X¹ is at least one element selected from the group consisting ofCo, Ni, V, Pt, and Rh;

[0006] X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W;

[0007] X³ is at least one element selected from the group consisting ofK, Mg, Rb, Ca, Sr, Ba, Na, and In;

[0008] a is 1;

[0009] b is 0<b<0.3, preferably 0.0000001<b<0.2;

[0010] c is 0<c<0.9, preferably 0.0001<c<0.5;

[0011] d is 0<d<0.9, preferably 0.0001<d<0.5;

[0012] e is 0<e<0.9, preferably 0.0001<e<0.5;

[0013] f is 0<f<0.9, preferably 0.0001<f<0.9;

[0014] g is 0<g<0.3, preferably 0.0000001<g<0.3; and

[0015] z is an integer representing the number of oxygen atoms requiredto satisfy the valency of the remaining components of the formula. Thecatalysts are preferably produced using the methods disclosed herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] One aspect of the invention relates to a catalyst for theproduction of alpha-beta unsaturated aldehydes from olefins andhydrocarbons. According to one embodiment, the catalyst composition hasthe formula:

Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z),

[0017] wherein

[0018] X¹ is at least one element selected from the group consisting ofCo, Ni, V, Pt, and Rh;

[0019] X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W;

[0020] X³ is at least one element selected from the group consisting ofK, Mg, Rb, Ca, Sr, Ba, Na, and In;

[0021] a is 1;

[0022] b is 0≦b<0.3, preferably 0.0000001<b<0.2;

[0023] c is 0≦c<0.9, preferably 0.0001<c<0.5;

[0024] d is 0≦d<0.9, preferably 0.0001<d<0.5;

[0025] e is 0≦e<0.9, preferably 0.0001<e<0.5;

[0026] f is 0≦f<0.9, preferably 0.0001<f<0.9;

[0027] g is 0≦g<0.3, preferably 0.0000001<g<0.3; and

[0028] z is an integer representing the number of oxygen atoms requiredto satisfy the valency of the remaining components of the formula.

[0029] According to a preferred embodiment of the invention, thecatalyst composition has the general formula

Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z),

[0030] wherein:

[0031] X¹ is at least one element selected from the group consisting ofCo, Ni, V, Pt, and Rh;

[0032] X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W;

[0033] X³ is at least one element selected from the group consisting ofK, Mg, Rb, Ca, Sr, Ba, Na, and In;

[0034] a is 1;

[0035] b is 0<b<0.3, preferably 0.0000001<b<0.2;

[0036] c is 0<c<0.9, preferably 0.0001<c<0.5;

[0037] d is 0<d<0.9, preferably 0.0001<d<0.5;

[0038] e is 0<e<0.9, preferably 0.0001<e<0.5;

[0039] f is 0<f<0.9, preferably 0.0001<f<0.9;

[0040] g is 0<g<0.3, preferably 0.0000001<g<0.3; and

[0041] z is an integer representing the number of oxygen atoms requiredto satisfy the valency of the remaining components of the formula. Thecatalysts are preferably produced using the methods disclosed herein.

[0042] Preferably, the catalyst is prepared from a solution of solublecompounds (salts, complexes, or other compounds) of each of the metals.The solution is preferably an aqueous system having a pH of 1 to 10, andmore preferably at a pH of 1 to 7, and the solution is maintained at atemperature of about 30° C. to about 100° C. Water is removed byfiltration to complete dryness, at which point the catalyst is dried inan oven at 100° C. to 130° C. for about 4 to about 24 hours. The driedcatalyst is calcined by heating to about 250° C. to about 600° C., about250° C. to about 450° C., in air or oxygen for about one hour to about16 hours to produce the desired catalyst composition.

[0043] The catalyst may be used with or without a support. If desired,suitable supports include alumina, silica, titania, zirconia, zeolites,silicon carbide, molybdenum carbide, molecular sieves, microporousmaterials, nonporous materials and mixtures thereof. Support materialcan be pretreated with acids such as HCl, HNO₃, H₂SO₄, per acids orheteroploy acids of phosphorous tungstate or silicotunstate, and alkalibases such as KOH or NaOH. When used on a support, the support usuallycomprises from about 50 to 95% by weight of the catalyst composition,with the remainder being the catalyst composition.

[0044] Preferably, molybdenum is introduced into the solution as anammonium salt, such as ammonium paramolybdate, or as an organic acidsalt of molybdenum. such as acetates, oxalates, mandelates, andglycolates. Some other partially water soluble molybdenum compoundswhich may be used in the present invention include molybdenum oxides,molybdic acid, and molybdenum chlorides.

[0045] Preferably, vanadium, bismuth, iron, cobalt, aluminum, gallium,silicon, germanium, antimony, phosphorous, niobium, potassium, magnesiumpalladium, tungsten, manganese are introduced as salts or acids, oxides,hydrate oxides, acetates, chlorides, nitrates, oxalates, or tartrates.

[0046] The method of the present invention is suitable for oxidation ofhydrocarbons and olefins to alpha-beta unsaturated aldehydes.Preferably, the feedstock includes lower branched or straight-chainedalkanes or alkenes, having C₂-C₆ carbon atoms. Further, the inventivecatalyst can also be applied for the ammoxidation of C₂-C₅. In apreferred embodiment the starting material is propylene and acrolein isproduced by the method.

[0047] The reaction mixture used in the method of the present inventionis generally a gaseous mixture of 0.1 to 99 mol % olefins, such aspropylene, 0.1 to 99 mol % molecular oxygen, either as pure oxygen or inthe form of air, 0 to 50 mol % water, in the form of steam, and 0 to 90mol % nitrogen or another inert gas. The gaseous mixture is generallyintroduced into the reaction zone at a temperature of about 150° C. toabout 500° C., preferably from 250° C. to 450° C.. The reaction zonegenerally has a pressure of from 1 to 50 bar, and preferably 1 to 30bar. The contact time between the reaction mixture and the catalyst ispreferably about 0.01 second to 100 seconds, and more preferably 0.1second to 10 seconds, and the space hourly velocity is about 50 to about50,000 h⁻¹, preferably about 100 to about 20,000 h⁻¹, and morepreferably from 500 to 10,000 h⁻¹.

[0048] According to one preferred embodiment, the method comprisescontacting a feed mixture comprising 1-50% by volume of olefins, 0.25 to50% by volume oxygen or a gas capable of providing oxygen, 0-50% byvolume steam and 10-80% by volume inert gas at a temperature of 170 to450° C. at a pressure of 15-500 psi at a space velocity of 500-20,000hr-1 with the catalyst. Preferably, the method provides a conversiongreater than 90%, more preferably greater than 95%, most preferablygreater than 98%, and a selectivity greater than 85%, more preferablygreater than 90%, most preferably greater than 95%. of the olefins tothe unsaturated aldehydes.

[0049] The process is generally carried out in a single stage in a fixedbed or fluidized bed or solid moving bed reactor with all the oxygen andreactants being supplied as a single feed and unreacted startingmaterials being recycled. However, multiple stage addition of oxygen tothe reactor with intermediate hydrocarbon feed can be used. This mayimprove productivity and avoid a potentially hazardous condition.

[0050] The following examples are intended to be illustrative of thisinvention. They are, of course, not to be taken to in any way limit thescope of this invention. Numerous changes and modifications can be madewith respect to the invention without departing from the spirit or scopeof the present invention.

EXAMPLES Example 1Mo₁Pd_(01.57e4)Bi_(0.09)Co_(0.8)Fe_(0.2)Al_(0.123)V_(4.69e-3)K_(5.33e-3)

[0051] Ammonium metavanadate (Aldrich Chemicals, Assay=99.0%), 0.11grams, was added to distilled water and heated to 90° C. with stirring.A yellow colored solution with pH between 4 and 7 was obtained (solutionA). Bismuth nitrate, 8.75 g, 16.2 grams of ferric nitrate, and 46.68grams of cobaltus nitrate were added with water to solution A withcontinuous stirring. Thereafter, the required amount of palladium,potassium and aluminum salt solutions were slowly added to the mixture.Ammonium paramolybdate tetrahydrate (Aldrich Chemicals A.C.S-12054-85-2), 35.4 grams, was added to the solution. This mixture wasthen dried. The resulting solid was dried in an oven at 100-120° C. Thedried material was cooled to room temperature and calcined in the rangeof 300 to 600° C. Calcined catalyst was formulated into uniformparticles of 40-60 mesh size and loaded in a stainless steel fixed bedtubular autoclave reactor.

[0052] The catalyst was tested with a gas feed composition ofnitrogen:oxygen:propylene:water in the ratio of 77:7.50:5.50:10 at 342°C., at a pressure of 15 psi, and a total flow of 130 cc/min. Thereaction product showed a 99% conversion of propylene with a 98%selectivity for acrolein.

Example 2 Mo₁Pd_(01.57e4)Bi_(0.09)Co_(0.8)Fe_(0.2)Al_(0.123)V_(4.69e-3)

[0053] Ammonium metavanadate (Aldrich Chemicals, Assay=99.0%), 0.11grams, was added to distilled water and heated to 90° C. with stirring.A yellow colored solution with pH between 4 and 7 was obtained (SolutionA). Bismuth nitrate, 8.75 g, 16.2 grams of ferric nitrate, and 46.68grams of cobaltus nitrate were added with water to solution A withcontinuous stirring, followed by the addition of the required amount ofpalladium and aluminum salts solution slowly to the mixture. Thereafter,ammonium 35.4 g paramolybdate tetrahydrate (Aldrich Chemicals A.C.S-12054-85-2) was added to the above solution. This mixture was thendried and the resulting solid was dried in an oven at 100-120° C. Thedried material was cooled to room temperature and calcined in the rangeof 300 to 600° C. Calcined catalyst was formulated into uniformparticles of 40-60 mesh size and loaded in a stainless steel fixed bedtubular autoclave reactor.

[0054] The catalyst was tested with a gas feed composition ofnitrogen:oxygen:propylene:water in the ratio of 77:7.50:5.50:10 at 342°C., at a pressure of 15 psi and a total flow of 130 cc/min. The reactionproduct showed a 93.2% conversion of propylene with a 87.4% selectivityfor acrolein

Example 3Mo₁Pd_(01.57e4)Bi_(0.09)Co_(0.8)Fe_(0.2)Al_(0.123)V_(4.69e-3)K_(5.33e-3)Ag_(0.0147)

[0055] Ammonium metavanadate (Aldrich Chemicals, Assay=99.0%), 0.11grams, was added to distilled water and heated to 90° C. with stirring.A yellow colored solution with pH between 4 and 7 was obtained (SolutionA). Bismuth nitrate, 8.75 g, 16.2 grams of ferric nitrate, and 46.68grams of cobaltus nitrate were added with water to solution A withcontinuous stirring, at which point the required amount of palladium,potassium, silver, and aluminum salt solutions were slowly to themixture. Thereafter, 35.4 g ammonium paramolybdate tetrahydrate (AldrichChemicals A.C.S -12054-85-2) was added to the solution. This mixture wasthen dried and the resulting solid was dried in an oven at 100-120° C.The dried material was cooled to room temperature and calcined in rangeof 300 to 600° C. Calcined catalyst was formulated into uniformparticles of 40-60 mesh size and loaded in a stainless steel fixed bedtubular autoclave reactor.

[0056] The catalyst was tested with a gas feed composition ofnitrogen:oxygen:propylene:water in the ratio of 77:7.50:5.50:10 at 342°C., at a pressure of 15 psi, and a total flow of 130 cc/min. Thereaction product showed a 97% conversion of propylene with a 98.6%selectivity for acrolein.

[0057] The catalysts disclosed in the present application exhibitmodified optimum redox behavior resulting in higher activity and yieldstowards the oxygenated products. Further, the inventive catalyst showedno deactivation until 8000 hrs on stream and achieved similar or higheryields (>95%) at relatively lower temperatures than mentioned in theprior art.

[0058] The above description of the invention is intended to beillustrative and not limiting. Various changes or modifications in theembodiments described may occur to those skilled in the art. These canbe made without departing from the spirit or scope of the invention.

1. A method for the production of unsaturated aldehydes from olefins,said method comprising contacting said olefins with an oxygen-containinggas in the presence of a catalyst in a reaction zone, said catalystcontaining a catalyst composition of the formula:Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z), wherein: X¹ is atleast one element selected from the group consisting of Co, Ni, V, Pt,and Rh; X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W; X³ is at least one elementselected from the group consisting of K, Mg, Rb, Ca, Sr, Ba, Na, and In;a is 1; b is 0<b<0.3; c is 0<c<0.9; d is 0<d<0.9; e is 0<e<0.9; f is0<f<0.9; g is 0<g<0.3; and z is an integer representing the number ofoxygen atoms required to satisfy the valency of Mo, Pd, Bi, Fe, X¹, X²,and X³ in the catalyst composition.
 2. The method of claim 1, whereinsaid catalyst is a supported catalyst comprising a support.
 3. Themethod of claim 2, wherein said support is selected from the groupconsisting of alumina, silica, titania, zirconia, zeolites, siliconcarbide, Mo-carbide, molecular sieves, microporous materials, nonporousmaterials, and mixtures thereof.
 4. The method of claim 2, wherein saidsupport is pretreated with an acid or base.
 5. The method of claim 2,wherein the supported catalyst comprises from about 5-50% by weight ofthe catalyst composition, with remainder being the support material. 6.The method of claim 1, wherein the aldehydes are alpha-beta unsaturated.7. The method of claim 1, wherein the olefins are lower branched orstraight-chained, having 2-6 carbon atoms.
 8. The method of claim 1,wherein said olefin is propylene and said method produces acrolein. 9.The method of claim 4, wherein said acid is selected from HCl, HNO₃,H₂SO₄, heteroploy acids of phosphorous tungstate or silicotungstate ormixtures thereof.
 10. The method of claim 2, wherein said support ispretreated with a base selected from the group consisting of KOH, NaOHor mixtures thereof.
 11. The method of claim 1, wherein said methodcomprises contacting a feed mixture comprising 1-50% by volume ofolefins, 0.25 to 50% by volume oxygen or a gas capable of providingoxygen, 0-50% by volume steam and 10-80% by volume inert gas at atemperature of 170 to 450° C. at a pressure of 15-500 psi at a spacevelocity of 500-20,000 hr-1 with the catalyst, and wherein said methodprovides a conversion greater than 98% and selectivity greater than 95%of said olefins to said unsaturated aldehydes.
 12. The method of claim11, wherein said olefins comprise propylene.
 13. The method of claim 11,wherein said catalyst is in the form of a fixed or fluidized bed orsolid moving bed reactor.
 14. The method of claim 1, wherein saidoxygen-containing gas comprises molecular oxygen.
 15. The method ofclaim 11, further comprising the multi-step introduction of oxygen intothe reaction zone to increase the yield, selectivity or both yield andselectivity of the corresponding unsaturated aldehydes.
 16. A method forperforming a catalytic chemical reaction in fluid phase for convertingone or more fluid phase reactants to one or more fluid phase productscomprising contacting a mixture containing said one or more fluid phasereactants with a catalyst under suitable reaction conditions in areaction zone to form said one or more fluid phase products, saidcatalyst containing a catalyst composition of the formula:Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z), wherein: X¹ is atleast one element selected from the group consisting of Co, Ni, V, Pt,and Rh; X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W; X³ is at least one elementselected from the group consisting of K, Mg, Rb, Ca, Sr, Ba, Na, and In;a is 1; b is 0<b<0.3; c is 0<c<0.9; d is 0<d<0.9; e is 0<e<0.9; f is0<f<0.9; g is 0<g<0.3; and z is an integer representing the number ofoxygen atoms required to satisfy the valency of Mo, Pd, Bi, Fe, X¹, X²,and X³ in the catalyst composition.
 17. The method of claim 16, whereinsaid one or more fluid phase reactants comprise molecular oxygen. 18.The method of claim 16, wherein said one or more fluid phase reactantscomprise olefin and said one or more fluid phase products comprisecorresponding unsaturated aldehydes.
 19. The method of claim 16, whereinsaid one or more fluid phase reactants comprise propylene and said oneor more fluid phase products comprise acrolein.
 20. The method of claim16, wherein said one or more fluid phase reactants comprise C₂-C₅olefins and oxygen and said one or more fluid phase products comprisecorresponding alpha-beta unsaturated aldehydes.
 21. The method of claim1, wherein said method is performed using a feed mixture comprisingbutylene and said method produces corresponding methacrolein.
 22. Themethod of claim 1, wherein said method is performed using a feed mixturecomprising C₂-C₅ alkanes, C₂-C₅ alkenes or mixtures thereof and saidmethod produces corresponding alpha-beta unsaturated aldehydes.
 23. Acatalyst for the production of unsaturated aldehydes from olefins, saidcatalyst comprising a catalyst composition having the formula:Mo_(a)Pd_(b)Bi_(c)Fe_(d)X¹ _(e)X² _(f)X³ _(g)O_(z), wherein: X¹ is atleast one element selected from the group consisting of Co, Ni, V, Pt,and Rh; X² is at least one element selected from the group consisting ofAl, Ga, Ge, Mn, Nb, Zn, Ag, P, Si, and W; X³ is at least one elementselected from the group consisting of K, Mg, Rb, Ca, Sr, Ba, Na, and In;a is 1; b is 0<b<0.3; c is 0<c<0.9; d is 0<d<0.9; e is 0<e<0.9; f is0<f<0.9; g is 0<g<0.3; and z is an integer representing the number ofoxygen atoms required to satisfy the valency of Mo, Pd, Bi, Fe, X¹, X²,and X³ in the catalyst composition.
 24. The catalyst of claim 23,further comprising a support.
 25. The catalyst of claim 24, wherein saidsupport is selected from the group consisting of alumina, silica,titania, zirconia, zeolites, silicon carbide, Mo-carbide, molecularsieves, microporous materials, nonporous materials, and mixturesthereof.
 26. The catalyst of claim 24, wherein the support is pretreatedwith an acid or base.
 27. The catalyst of claim 24, wherein thesupported catalyst comprises from about 5-50% by weight of the catalystcomposition, with remainder being the support material.
 28. A processfor making the catalyst of claim 23, comprising: (a) forming a mixtureMo, Pd, Bi, Fe, X¹, X², and X³ in a solution; (b) drying said mixture toform a dried solid material; and (c) calcining said dried solid materialto form said catalyst.
 29. The process of claim 28, wherein said mixtureis an aqueous system having a pH from 1 to
 10. 30. The process of claim28, wherein said mixture is an aqueous system having a pH from 1 to 7.31. The process of claim 28, wherein said calcining comprises heatingsaid dried solid material at a calcining temperature from about 250 to450° C. in air or oxygen for a period of time from about one hour toabout 16 hours.